Vehicles are conventionally driven by one or more propelling members which themselves are driven by a drive means to result in the vehicle being driven in a desired direction.
For land vehicles, propelling members usually comprise ground engaging wheels which function to support the land vehicle from the ground and also to propel the vehicle along the ground. Ground engaging wheels for land vehicles are conventionally of a circular construction and are rotatably mounted to an axle which itself is mounted to the vehicle or to attachment thereto such as a suspension assembly. The axle generally extends at right angles to the propulsion direction of the vehicle and the vehicle wheel is mounted such that the plane along which the vehicle wheel extends is at right angles to the axle. In other words, the plane through which the vehicle wheel extends is substantially in alignment to the propulsion direction of the vehicle.
To allow land vehicles to be self-supporting there are provided wheels on each side of the vehicle. These wheels are positioned parallel relative to each other. Tracked vehicles have the same above arrangements however include an endless track extending about the vehicle wheels.
Such conventional wheels suffer from a number of disadvantages. Firstly, wheels of the above construction are generally not suitable for soft ground surfaces such as mud, snow or sand as under such conditions, the wheels tend to sink into the ground. If the wheels are of the driven type, they tend to merely spin about their axes without gripping the ground. To overcome the above disadvantage, it is known to attach various ground gripping devices to the wheels or to use endless tracks extending about the wheels to improve ground adhesion.
A second disadvantage with conventional wheels is that for vehicles having at least front or rear wheels, the rear wheels tend to follow the tracks made by the front wheels. This results in ruts being formed in the ground and with soft ground surfaces easily results in a vehicle becoming bogged. This latter problem is particularly troublesome for convoys of vehicles travelling across soft ground surfaces as the latter vehicles of the convoy find it extremely difficult to maintain adequate ground adhesion due to the ruts formed by the first vehicles.
For marine vehicles such as boats, propellers are the main method to propel the vehicle through water. The propellers typically comprise a hub portion and a number propeller blades extending radially about the hub portion. The propeller is such that the rotation axes is generally in alignment with the propulsion direction of the vehicle.
Paddle wheels are also used to propel marine vehicles and comprise a number of paddle wheel blades extending about a hub member.
A disadvantage with such propulsion units is that they are limited only to water vehicles and will not function to propel a vehicle along a ground surface. Thus, with amphibious vehicles it has hitherto been necessary to provide such vehicles with a number of land wheels of the conventional type and a marine type propeller. This is cumbersome and adds to the cost of the vehicle and the conventional land wheels suffer from the disadvantages mentioned above.
It is known to provide an amphibious vehicle only with land wheels and to provide the wheels with a particular tread pattern which provides some degree of propulsion through water. However, these vehicles are slow and cumbersome in water as the wheels have been principally designed for movement along a non-liquid surface.
It is an object of the invention to provide a propelling member and assembly which may alleviate the above mentioned disadvantages.
It is a preferred object of the invention to provide a propelling member and assembly which can be attached to vehicles to allow the vehicles to be propelled along solid ground surfaces or through water or along soft ground surfaces.